1. Field of the Invention
This invention relates to a coating mask device used for applying a coating only to a desired portion of a molded product serving as a component part of a lighting device for a vehicle.
2. Related Art
In a conventional coating mask device of this type shown in FIGS. 9 and 10, a support jig 2, on which a lens 3 (which is a component part of a lighting device) can be placed, is supported on a support base 1; and a mask body 4 is provided so as to cover the lens 3 placed on the support jig 2. An opening 4a is formed through that portion of the mask body 4 corresponding to a coat-forming region 3a of the lens 3. A spray coating is applied from the upper side of the opening 4a (as indicated by broken lines in FIG. 9), thereby applying a coating only to the desired portion (i.e., the coat-forming region 3a) of the lens 3.
The mask body 4 is integrally formed with an upper frame 5, and can be pivotally moved about a horizontal axis 1a disposed at the support base 1. The mask body 4 can be opened and closed relative to the jig 2 as shown in FIG. 10, and with this construction the lens 3 can be placed on and removed from the support jig 2. The upper frame 5 can be retained relative to the support base 1 by a hook 6.
The upper frame 5, having the mask body 4 integrally formed therewith, can be removed from the support base 1 at the horizontal axis 1a. Three upper frames 5 of the same specification, each having the mask body 4 integrally formed therewith, are prepared beforehand. The mask body 4 (and hence the upper frame 5), which has been stained after long use in the coating process, is removed from the support base 1 for cleaning purposes, and a new mask body 4 (and new upper frame 5) of the identical specification and kept in store, is mounted on the support base 1, and is used.
Namely, when the mask body 4 is used for a long period of time, a thick coating layer is deposited on the peripheral edge portion of the opening 4a, and this can prevent proper coating. Therefore, each time a predetermined number of (for example, one hundred) products are coated, the mask body 4 (and the upper frame 5) is replaced by a new one.
In the above conventional coating mask device, however, even if the coat-forming region 3a is one portion of the component part of the lighting device, the mask body 4 is formed into such a size as to cover the whole of the lighting device component part, and, therefore, the following problems have been encountered.
First, since the mask body 4 has a large size, extensive time is required for forming the mask body 4, and the cost increases.
Second, since the mask body 4 has a large size, it is heavy and can not be easily handled.
Third, generally, for cleaning the mask body 4 (and hence the upper frame 5), several mask bodies 4 are put into a cleaning cage, and then this cage is dipped in a cleaning liquid in which ultrasonic cleaning is effected. However, since the mask body 4 has a large size, the number of the mask bodies which can be put into the cage is limited, and the efficiency of the cleaning operation is poor. Moreover, a large amount of cleaning liquid is required.
Fourth, since the mask body 4 has a large size, a large space is required for storing the other two mask bodies (and the upper frames) not yet used.
Fifth, when the design or configuration of the lighting device component part is changed, all of the three mask bodies 4 must be modified which is inefficient and expensive.
With the above problems in mind, it is an object of this invention to provide a coating mask device for a lighting device in which a mask body is divided into a plurality of sections so that the mask body can be easily handled.
According to the present invention, there is provided a coating mask device for a lighting device comprising a support jig, on which a component part of the lighting device can be placed, and a mask body arranged so as to cover the lighting device component part placed on the support jig, the mask body having an opening corresponding to a coat-forming region of the lighting device component part; wherein the mask body is divided into a partial mask having the opening, and a main mask for covering that region of the component part other than that region covered by the partial mask; and wherein the partial mask is removable from the main mask.
For example, three partial exchangeable masks are prepared for one main mask. Each partial mask, having the opening corresponding to the coat-forming region of the lighting device component part, is smaller in size than the mask body, and, therefore, can be processed. The partial mask is compact and lightweight, and, therefore, can be easily handled. Moreover, the required storage space is small, and many partial masks can be put into a cleaning cage at a time. Therefore, the efficiency of the cleaning operation is high, and the amount of a cleaning liquid required is small. Furthermore, if a portion of the lighting device component part, corresponding to the main mask, is changed in configuration, it is only necessary to modify the main mask, and the partial mask does not need to be modified.
According to an embodiment of the present invention, the partial mask and the main mask overlap each other at their joining portions at which the two masks are joined together, thereby preventing coating material from being applied to a region other than the coat-forming region of the lighting device component part.
According to another embodiment of the present invention, the support jig is supported on a support base, and each of the partial mask and the main mask is pivotally movable upwardly and downwardly about a respective horizontal axis disposed at the support base so as to be opened and closed relative to the support jig, and the partial mask is disposed near the horizontal axis of pivotal movement of the main mask.
When the partial mask,.having the opening corresponding to the coat-forming region of the lighting device component part, is disposed near the horizontal axis of pivotal movement of the main mask, an error in the positioning of the opening relative to the coat-forming region of the component part is smaller when compared to the case where the partial mask is disposed remote from the horizontal axis.
According to yet another embodiment of the present invention, the horizontal axis of pivotal movement of the partial mask and the horizontal axis of pivotal movement of the main mask are the same.
It is preferred that the horizontal axis of pivotal movement of the partial mask should be disposed at the predetermined position close to the horizontal axis of pivotal movement of the main mask in such a manner that the partial mask will not interfere with the support jig. If the horizontal axis of pivotal movement of the partial mask and the horizontal axis of pivotal movement of the main mask are the same, an error in the positioning of the opening is further reduced, and the two masks can be easily designed.